But some questions remained: Why does he have it? And is this array – of 14kW of rooftop solar and 14kWh of battery storage (LG Chem lithium ion) enough to take the average home off grid?

We don’t know the answer to the why’s and wherefore’s, because his office is staying Mum on the issue, although apparently the PM delights in showing his monitoring software of the solar output and battery storage operations in his Canberra office. At least he hasn’t totally lost his interest in new technology.

As for going off-grid: well, in the case of Turnbull’s house, that array almost certainly is not even close to being big enough to take his Point Piper mansion off grid. The 14kW solar array would probably generate an average of 50-56kWh of electricity a day, with around 90kWh on sunny days, depending on the set-up.

But we’re going to take a guess and assume that his harbourside mansion consumes more than the average home of 16-20kWh a day. It’s probably treble that amount if you think of all the electronic gadgetry, pool pumps, security gate etc that there could be.

That also means that Turnbull doesn’t have anyway near enough to go off grid. To do that he would likely need 100kWh. And what he has is a relatively small sized battery array for the amount of panels, experts say. But, depending on the set-up of his LG Chem battery storage system, and the inverters in use, it could give him power if the grid went down.

What about for the average home? Would this array be enough to go off-grid?

Experts say that it’s more than enough solar, but possibly not quite enough battery storage. One or two suggest an average home in a sunny area could get by, although three or four days or rainy weather would put it to the test, even with a solar array still producing at around 20 per cent of capacity in those conditions.

Matthew Wright, the head of Pure Electric Solutions, says the combination would not be far off what would be required for Sydney. Winter could be a challenge, but a low consumption, super efficient home could get by.

“If you had either gas for heating (average home) or super efficient air conditioner heat pumps such as the Daikin US7 with a tight building envelope it would do the trick.”

Steve Madson, from Country Solar in Queensland, also says that without bad weather, that array would be sufficient for many homes with low consumption. “I have 10kwh (battery storage) in Townsville and that gets through with air conditioning,” he says.

Shaun Beck, the manager of Solar City, in the Hunter Valley, says Turnbull’s array would be enough to keep some homes off the grid, even if it is heavy on solar and a bit light on storage.

“For an off grid system 14kw is a bit of over kill and the storage a bit low, but it all depends how much power they would need daily,” Beck says.

As for Turnbull’s array, the solar system would likely produce as little as 10-14kwh, or even less if really bad. “So 14kwh storage won’t mean a lot (for going off-grid). I’m sure that won’t worry the uber rich.”

Others are more conservative. For them, the general rule is for storage to be three times the average consumption, to keep the lights on in bad weather. Or use a generator.

But as one said, by having a very big solar array and relatively small battery storage, Turnbull is probably exporting a fair amount back to the grid on sunny days (assuming that the household is not a complete power guzzler).

In that respect, he is probably doing his bit to keep a lid on wholesale electricity prices. “It’s probably the best thing he has done for electricity costs since he became prime minister,” the storage expert said.

This article was originally published on RE sister site, One Step Off The Grid. To sign up for the weekly newsletter, click here.

Giles Parkinson is founder and editor of Renew Economy, and is also the founder of One Step Off The Grid and founder/editor of The Driven. Giles has been a journalist for 35 years and is a former business and deputy editor of the Australian Financial Review.

Giles Parkinson is founder and editor of Renew Economy, and is also the founder of One Step Off The Grid and founder/editor of The Driven. Giles has been a journalist for 35 years and is a former business and deputy editor of the Australian Financial Review.

“It’s probably the best thing he has done for electricity costs since he became prime minister”

Very droll.

trackdaze 3 years ago

Lets assume the 14kwhr is there or there abouts for average use and in bouts of bad weather he simply tap into the 70+kwhr battery reserves in the tesla ev i see in his future.

Trent Deverell 3 years ago

14kwhr of battery is not much in context to the likely electrical demand of the mansion

But given Malcolm’s latest penchant for pumped hydro, an LP system powered by likely daytime excess from 14kwp of PV…. might just work on his block – if he can engineer a big enough tank on the top level…

Can only dream about it….

solarguy 3 years ago

Since were on the subject of off grid systems, which range in size from 300watt PV Array’s right up to Jesus Christ that’s a lot of panels and a shit load of batteries, it would be good to have some perspective.

The average home consumes between 15-22kwh/day, but let’s not be pedantic on averages or whether that home has an A/C or not, let’s just say the av max consumption is deemed to be 22kwh/day in winter. Now in bad weather PV output can be way down or even worse bugger all, so there has to be enough storage (autonomy) for 3 days use before batteries need to be recharged by either solar or generator. The battery bank, as a rule of thumb needs to be at least, 66kwh usable. Hopefully after 3 days the bad weather has gone and sunny days are here again. You could go for 2 days autonomy, if you are prepared to go easy on the juice.

The PV array would need to be as a rule of thumb, at the very least 6kw for latitude 32.5 degrees south. This is based on average June solar insolation, allowing for battery charging efficientcy and inverter efficiency. North or south of this latitude would be a different story depending how far.

So for any one who is thinking going off grid there are 2 things to consider; Oversizing PV Array’s, can reduce battery size required. Doubling to 12kw will still only generate about 10kwh/day when it’s overcast, or light rain or even less and up to 50kwh on good sunny days. The point here is, it’s a balance and some off grider’s will use less power to compensate. Ask yourself this question, would use less power in times when generation is low for days on end or will you start the genset and run it for hours, chewing through plenty of expensive petrol.

If you need as much power as the above example every day think again, if think your going to do it with just 10kwh of storage!

wmh 3 years ago

Our Prime Minister could save some of the expense of the extra batteries by storing excess solar energy on sunny days in his electric hot water service. Hot water uses an annualised 25% of domestic energy (Ausgrid data). I assume that he is already net-metered so it would just be a matter of connecting a power diverter between the lower heating element and his normal heating circuit breaker. A power diverter senses the power flow to and from the grid and takes advantage of the meter’s fixed increment size, generally 1Whr, to balance grid power to the heater with PV power to the grid.

Radbug 3 years ago

Lithium-ion is old hat. The future is Lithium-sulphur. The R&D frenzy is on to gather up the IP. Li-S has a specific capacity of 1675 mAh/gm versus 300 mAh/gm for Li-ion. Once Li-S is up, we’ll be in a new world. Everyone will be driving electric cars. I expect that there’ll be a terrific load on the generators. It’ll be very interesting to see the political implications of this. ps. I still love Solar Methanol & DMFC’s.

GregX 3 years ago

My guess is that Malcolm will soon have these solar panels and batteries removed so he can install a shiny new coal fired personal generator. He can then go off grid knowing he is doing “good for humanity”. It will be ultra clean setup so the neighbours won’t mind at all. Heck, the house is that old, it probably still has a coal store.

Peter 3 years ago

This is a back of the envelope calculation base on data I collected in 2014-15. My house (Lat 38S) consumes 4MWh of electrical energy per annum. Hence, to be off grid for a bad week in winter requires, say, 77kWh of battery storage. To charge such a battery in a good week while supplying the house, would requires the generation of twice that, of 154kWh. In winter, my 3kW array averages say 5kWh a day. So, I need a 13kW PV array. (This calculation assumes that the panels generate zero energy during a week of bad days, which is pessimistic).